When this is false, it can reduce the response payload size, which might lead to better performance in some environments.

quotaUser

Alternative to userIp.

Lets you enforce per-user quotas from a server-side application even in cases when the user's IP address is unknown. This can occur, for example, with applications that run cron jobs on App Engine on a user's behalf.

You can choose any arbitrary string that uniquely identifies a user, but it is limited to 40 characters.